Designed & Made in the USA Since 1983
Nearly four decades gauging for automotive, aerospace, and major glass manufacturers. LMI builds MicroRidge’s RM2.4 wireless into it’s main product families.
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AGC Automotive, Pilkington, NSG, Fuyao, and Vitro are five of the largest automotive glass manufacturers in the world. When each of them needed to standardize its glass measurement process on a single platform, all five landed on gauging from Linear Measurement Instruments (LMI Corporation) of Fenton, Michigan. Trust like that gets built gauge by gauge, on the shop floor, over nearly four decades. It’s also why LMI made a decision most gauge manufacturers haven’t: building MicroRidge’s RM2.4 wireless protocol directly into its main product families, rather than treating wireless as an aftermarket add-on.
Linear Measurement Instruments was founded in 1988. Its first product was developed to meet a specific measurement need at General Motors, and that first purchase order became the foundation for a company that now supplies precision gauging to automotive, aerospace, and glass manufacturers worldwide. GM later recognized LMI with its “People Make Quality Happen Award” in 2003, for the measurement tools, software, and support behind 27 GM Fit Gate stations. Today LMI operates an ISO 9001:2015 certified quality management system and maintains manufacturing operations in Fenton, Michigan, and Madison, Alabama.
If a tier one supplier is making sheet metal, glass, or plastic parts for an OEM, there’s a good chance LMI gauges are measuring those parts or sitting on the fixtures that check them. The company’s LMI 200 series probe, a spring-loaded surface contact transducer, has become a standard component of checking fixtures across much of the automotive industry. The same probe design is used in aerospace applications, from wing surface contour checks to 747 fuselage frame station verification.
Automotive glass stands out from the rest, not because the parts are harder to measure but because of the sheer volume of data those plants collect. Glass manufacturers run electronic data collection at a scale well beyond what’s typical in metal stamping or plastic molding. LMI has supplied measurement tools to that sector for more than 20 years. AGC Automotive, Pilkington, NSG, Fuyao, and Vitro, which together account for the large majority of automotive glass produced globally, have standardized on LMI gauging for size and form checks, using the LMI 241-B gauge mounted to LMI’s patented 776 block system to hold Gauge R&R below 5% at every checkpoint.
Ask a quality manager what fails first on a wired data collection setup and the answer usually isn’t the instrument. It’s the cable. Cables get pinched under fixtures, walked on, rolled over, yanked at the connector, and flexed until a conductor breaks somewhere inside the jacket where nobody can see it. When that happens, a perfectly good gauge stops reporting, or worse, reports intermittently. Then the readings get keyed in by hand until somebody orders a replacement cable, and the audit trail develops a gap.
LMI’s answer was to design the cable out of the equation entirely. Every main product family (the LMI 200 series probe, the 241 Gap and Flush gauge, the True Position probe, the Diamondback indicator, and the Seal Gap gauge) is available with MicroRidge’s RM2.4 wireless built directly into the instrument. Removing the cable eliminated the single most common failure point on the floor. It also changed how fast a station can move: no cable to route, no fixed distance to a data collection PC, and no operator waiting on a connection to log a reading. Data collection efficiency went up, and so did operator satisfaction, which matters more than it sounds when the alternative is a gauge that fights you every shift.
The Diamondback (D-Back) is LMI’s shop-hardened digital indicator, built with an aluminum housing and a hardened stainless steel stem and spindle specifically to survive drops, impacts, and continuous production use that damage conventional indicators. It’s available with ½” or 1″ travel, 3/8″ or 8.0mm diameter stems, and delivers .0005″/.01mm resolution with Absolute Mode, Tolerance Judgment, and a Button Lock that prevents accidental setting changes mid-shift. A two-piece tip design and a rubber protective boot address the two most common failure points on shop-floor indicators: broken tips and impact damage to the housing.
One early adopter, a Michigan-based automotive supplier’s quality engineering team, reported that the digital indicators previously used in their plant did not survive being dropped or having a part land on them. The Diamondback held up under the same conditions. For a gauge that lives at a fixture station instead of a climate-controlled lab, that kind of durability data point matters as much as resolution and accuracy specs.
The Diamondback supports USB, Digimatic, and Serial (RS-232) output. The Wireless Diamondback goes a step further, with the RM2.4 radio inside the instrument itself.
True Position is one of the most heavily used GD&T controls on stamped, cast, and machined parts because it does something a simple X/Y linear dimension can’t: it defines a single tolerance zone around a feature’s nominal location, evaluated from a specified datum reference frame, instead of stacking up separate plus and minus tolerances on two axes. On a production part, that shows up constantly. Weld nut and stud locations on a body-in-white structure, hinge and latch mounting holes on a closure panel, dowel and locating pin holes that establish a fixture’s own datum scheme, seat track and bracket mounting patterns, and fastener hole patterns on aerospace skin panels and structural members. Anywhere a mating part, a fastener, or another assembly has to land in the right spot, there’s a good chance it’s controlled by a true position callout.
LMI’s True Position probes check that callout directly at the fixture. The probe contacts the hole or slot and reports deviation on two independent axes, typically labeled A and B, from the nominal location in a single touch. That’s a meaningful step up from a go/no-go pin gauge: instead of a pass or fail, the operator gets variable data on exactly how far off, and in which direction, the hole has drifted. Trended over a production run, that data can flag a wearing weld-nut locator or a shifting fixture datum well before it produces a part that fails a pin gauge outright, the same early-warning value that makes variable data preferable to attribute data anywhere else in an SPC program.
Because the probe is designed to work across multiple gauges and fixtures rather than being hardwired into one, a shop can standardize on a small number of True Position probes and move them between checking stations as needed, rather than dedicating a probe permanently to every fixture. That’s a real cost and calibration-management advantage for a facility running dozens of fixture stations: fewer gauges to purchase, fewer gauges to send out for calibration, and one consistent measurement method across every true position check in the plant.
Most gauges come onto a wireless data collection network through an external transmitter clipped to the instrument’s own SPC output. That’s still the right approach for a lot of a shop’s gauge fleet, and MicroRidge’s Mini Mobile Module EVO and other transmitters cover calipers, micrometers, and indicators from dozens of manufacturers this way. LMI took a different route across its own product line.
The wireless versions of LMI’s gauges ship with MicroRidge’s RM2.4 wireless protocol built into the instrument. The protocol matters as much as the decision to go wireless at all. RM2.4 is built on IEEE 802.15.4 and holds a single clean channel rather than hopping across a crowded 2.4 GHz band, which is why Bluetooth-based gauge systems struggle on a real shop floor. There’s no external transmitter to clip on and no cable at the station. Pair the gauge to a MobileCollect Base Receiver and readings flow straight into SPC software or a spreadsheet.
The practical result for a tier one supplier is a single RM2.4 network that carries both kinds of gauges at once: LMI’s wireless-native instruments alongside calipers, micrometers, and indicators from other manufacturers connected through Mini Mobile Modules or other MicroRidge transmitters. Every reading lands on the same Base Receiver, in the same data format, regardless of how the gauge joined the network.
That matters more as data volumes grow. Control plans under IATF 16949 call for consistent, traceable measurement records at every checkpoint, not just the ones running a single instrument type. A True Position check at a body-in-white fixture, a gap and flush reading on a closure panel, and a size check on a windshield are three different measurement types from three different parts of the plant. On a single MobileCollect backbone, they land in the same SPC data stream, in the same format, whether the gauge has RM2.4 built in or reaches the network through a transmitter.
“The number one failure we saw in the field was never the gauge, it was the cable. Building wireless inside the instrument took that failure mode off the table, and it turned out to make the data collection itself faster. Our customers shouldn’t have to choose between a gauge that survives the shop floor and one that gets its data where it needs to go.”
Brian Green, President, Linear Measurement Instruments
LMI didn’t have to build wireless into its gauges. The trust was already there: a GM quality award, standardization across the world’s largest automotive glass manufacturers, and decades of ISO 9001 certified production. Doing it anyway, across every main product family rather than one flagship instrument, says something about how LMI approaches the gauges its customers depend on. Durable enough to survive the shop floor, and built from the start to get a reading off that floor without a cable, a clip-on transmitter, or a hand-written number.
That’s the same standard a quality team should expect from the rest of its gauge fleet. Whether a reading comes from an LMI instrument with wireless built in or a caliper connected through a Mini Mobile Module, it lands on the same MobileCollect network, in the same format, ready for whatever the plant runs on.
The cable was never the interesting part of the measurement. It was just the part that broke. LMI designed it out of their gauges. MicroRidge built the network those gauges talk on. If you’re already running LMI gauges, ask which of your models are available with wireless built in. If you’re trying to get a mixed-brand fixture line onto one data stream, request a Demo Kit and run RM2.4 in your own plant, with your own gauges, in your own RF environment.
101 North Alloy Drive
Fenton, MI 48430 USA
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Email: sales@lmicorporation.com
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MicroRidge designs and manufactures gage data collection solutions for manufacturing quality teams who need real-time, accurate measurement data without manual entry. Learn more about MobileCollect Wireless or contact MicroRidge directly.